CROSS REFERENCES
BACKGROUND
[0001] The following relates generally to wireless communication, and more specifically
to the transmission of a cyclic redundancy check (CRC) for uplink control information
(UCI) on control and data channels.
[0002] Wireless communications systems are widely deployed to provide various types of communication
content such as voice, video, packet data, messaging, broadcast, and so on. These
systems may be capable of supporting communication with multiple users by sharing
the available system resources (
e.g., time, frequency, and power). Examples of such multiple-access systems include code
division multiple access (CDMA) systems, time division multiple access (TDMA) systems,
frequency division multiple access (FDMA) systems, and orthogonal frequency division
multiple access (OFDMA) systems, (
e.g., Long Term Evolution (LTE) or LTE-Advanced (LTE-A) systems). A wireless multiple-access
communications system may include a number of base stations, each simultaneously supporting
communication for multiple communication devices, which may be otherwise known as
user equipment (UE).
[0003] Some modes of communication may enable communications between a base station and
a UE over a shared radio frequency spectrum band, or over different radio frequency
spectrum bands (
e.g., a dedicated radio frequency spectrum band and a shared radio frequency spectrum band)
of a cellular network. With increasing data traffic in cellular networks that use
a dedicated (
e.g., licensed) radio frequency spectrum band, offloading of at least some data traffic
to a shared radio frequency spectrum band may provide a cellular operator with opportunities
for enhanced data transmission capacity. A shared radio frequency spectrum band may
also provide service in areas where access to a dedicated radio frequency spectrum
band is unavailable.
[0004] Some modes of communication may enable communications between a base station and
a UE over multiple component carriers in parallel (
e.g., when the base station and the UE operate in a carrier aggregation (CA) mode), or
enable communications between multiple base stations and a UE over multiple component
carriers in parallel (
e.g., when the base stations and the UE operate in a dual-connectivity mode).
[0005] In some examples, communications between a base station and a UE over a shared radio
frequency spectrum band and/or communications between a base station and a UE over
multiple component carriers in parallel, may reduce the reliability of the communications
compared to communications between a base station and a UE over a single component
carrier in a dedicated radio frequency spectrum band (
e.g., a licensed radio frequency spectrum band usable for LTE/LTE-A communications).
SUMMARY
[0007] In accordance with the present invention, there is provided a method as set out in
claim 1, an apparatus as set out in claim 6 and a computer program product as set
out in claim 13. Other aspects of the invention are set out in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Aspects of the disclosure are described in reference to the following figures:
FIG. 1 illustrates an example of a wireless communications system that supports transmission
of cyclic redundancy check (CRC) for uplink control information (UCI) on control and
data channels in accordance with various aspects of the present disclosure;
FIG. 2 illustrates an example of a wireless communication system in which Long Term
Evolution (LTE)/LTE Advanced (LTE-A) may be deployed under different scenarios using
a dedicated radio frequency spectrum band or a shared radio frequency spectrum band
in accordance with various aspects of the present disclosure;
FIG. 3 illustrates an example of a wireless communication over a shared radio frequency
spectrum band in accordance with various aspects of the present disclosure;
FIG. 4 illustrates an example of a wireless communication system in which LTE/LTE-A
may be deployed under different scenarios using a dedicated radio frequency spectrum
band or a shared radio frequency spectrum band in accordance with various aspects
of the present disclosure;
FIG. 5 illustrates a wireless communication system in which LTE/LTE-A may be deployed
in a carrier aggregation scenario in accordance with various aspects of the present
disclosure;
FIG. 6 illustrates a wireless communication system in which LTE/LTE-A may be deployed
in a dual-connectivity scenario (e.g., a coordinated multipoint (CoMP) scenario) in accordance with various aspects of the
present disclosure;
FIGs. 7-9 show block diagrams of a wireless device that supports transmission of CRC
for UCI on control and data channels in accordance with various aspects of the present
disclosure;
FIG. 10 illustrates a block diagram of a system including a user equipment (UE) that
supports transmission of CRC for UCI on control and data channels in accordance with
various aspects of the present disclosure; and
FIGs. 11-14 illustrate methods to transmit a CRC for UCI on control and data channels
in accordance with various aspects of the present disclosure.
DETAILED DESCRIPTION
[0009] Methods, systems, and devices are described for wireless communication. The methods,
systems, and devices may increase the reliability of transmitting uplink control information
(UCI) on control and data channels by using a cyclic redundancy check (CRC) for a
user equipment (UE) under at least some conditions.
[0010] FIG. 1 illustrates an example of a wireless communication system 100 that supports transmission
of CRC for UCI on control and data channels, in accordance with various aspects of
the disclosure. The wireless communication system 100 may include base stations 105,
UEs 115, and a core network 130. The core network 130 may provide user authentication,
access authorization, tracking, Internet Protocol (IP) connectivity, and other access,
routing, or mobility functions. The base stations 105 may interface with the core
network 130 through backhaul links 132 (
e.g., S1,
etc.) and may perform radio configuration and scheduling for communication with the UEs
115, or may operate under the control of a base station controller (not shown). In
various examples, the base stations 105 may communicate, either directly or indirectly
(
e.g., through core network 130), with each other over backhaul links 134 (
e.g., X1,
etc.)
, which may be wired or wireless communication links.
[0011] The base stations 105 may wirelessly communicate with the UEs 115 via one or more
base station antennas. Each of the base station 105 sites may provide communication
coverage for a respective geographic coverage area 110. In some examples, a base station
105 may be referred to as a base transceiver station, a radio base station, an access
point, a radio transceiver, a NodeB, an eNodeB (eNB), a Home NodeB, a Home eNodeB,
or some other suitable terminology. The geographic coverage area 110 for a base station
105 may be divided into sectors making up a portion of the coverage area (not shown).
The wireless communication system 100 may include base stations 105 of different types
(
e.g., macro or small cell base stations). There may be overlapping geographic coverage
areas 110 for different technologies.
[0012] In some examples, the wireless communication system 100 may include a Long Term Evolution
(LTE)/LTE Advanced (LTE-A) network. In LTE/LTE-A networks, the term evolved Node B
(eNB) may be used to describe the base stations 105, while the term UE may be used
to describe the UEs 115. The wireless communication system 100 may be a Heterogeneous
LTE/LTE-A network in which different types of eNBs provide coverage for various geographical
regions. For example, each eNB or base station 105 may provide communication coverage
for a macro cell, a small cell, or other types of cell. The term "cell" is a "3rd
Generation Partnership Project" (3GPP) term that can be used to describe a base station,
a carrier or component carrier associated with a base station, or a coverage area
(
e.g., sector,
etc.) of a carrier or base station, depending on context.
[0013] A macro cell may cover a relatively large geographic area (
e.g., several kilometers in radius) and may allow unrestricted access by UEs with service
subscriptions with the network provider. A small cell may be a lower-powered base
station, as compared with a macro cell that may operate in the same or different (
e.g., dedicated, shared,
etc.) radio frequency spectrum bands as macro cells. Small cells may include pico cells,
femto cells, and micro cells according to various examples. A pico cell may cover
a relatively smaller geographic area and may allow unrestricted access by UEs with
service subscriptions with the network provider. A femto cell also may cover a relatively
small geographic area (
e.g., a home) and may provide restricted access by UEs having an association with the femto
cell (
e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like).
An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell
may be referred to as a small cell eNB, a pico eNB, a femto eNB or a home eNB. An
eNB may support one or multiple (
e.g., two, three, four, and the like) cells (
e.g., component carriers).
[0014] The wireless communication system 100 may support synchronous or asynchronous operation.
For synchronous operation, the base stations may have similar frame timing, and transmissions
from different base stations may be approximately aligned in time. For asynchronous
operation, the base stations may have different frame timing, and transmissions from
different base stations may not be aligned in time. The techniques described herein
may be used for either synchronous or asynchronous operations.
[0015] The communication networks that may accommodate some of the various disclosed examples
may be packet-based networks that operate according to a layered protocol stack. In
the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP)
layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation
and reassembly to communicate over logical channels. A Medium Access Control (MAC)
layer may perform priority handling and multiplexing of logical channels into transport
channels. The MAC layer may also use Hybrid Automatic Repeat Request (HARQ) to provide
retransmission at the MAC layer to improve link efficiency. In the control plane,
the Radio Resource Control (RRC) protocol layer may provide establishment, configuration,
and maintenance of an RRC connection between a UE 115 and the base stations 105 or
core network 130 supporting radio bearers for the user plane data. At the Physical
(PHY) layer, the transport channels may be mapped to physical channels.
[0016] The UEs 115 may be dispersed throughout the wireless communication system 100, and
each UE 115 may be stationary or mobile. A UE 115 may also include or be referred
to by those skilled in the art as a mobile station, a subscriber station, a mobile
unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless
device, a wireless communications device, a remote device, a mobile subscriber station,
an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset,
a user agent, a mobile client, a client, or some other suitable terminology. A UE
115 may be a cellular phone, a personal digital assistant (PDA), a wireless modem,
a wireless communication device, a handheld device, a tablet computer, a laptop computer,
a cordless phone, a wireless local loop (WLL) station, or the like. A UE may be able
to communicate with various types of base stations and network equipment, including
macro eNBs, small cell eNBs, relay base stations, and the like.
[0017] The communication links 125 shown in wireless communication system 100 may include
downlink (DL) transmissions, from a base station 105 to a UE 115, or uplink (UL) transmissions,
from a UE 115 to a base station 105. The downlink transmissions may also be called
forward link transmissions, while the uplink transmissions may also be called reverse
link transmissions. In some examples, UL transmissions may include transmissions of
uplink control information, which uplink control information may be transmitted over
an uplink control channel (
e.g., a physical uplink control channel (PUCCH) or enhanced PUCCH (ePUCCH)). The uplink
control information may include, for example, acknowledgements (ACKs) or non-acknowledgements
(ACKs) of downlink transmissions, scheduling requests (SRs) or enhanced SRs (eSRs),
or channel state information (CSI). UL transmissions may also include transmissions
of data, which data may be transmitted over a physical uplink shared channel (PUSCH)
or enhanced PUSCH (ePUSCH). References in this disclosure to a PUCCH, a PUSCH, or
an SR are presumed to inherently include references to a respective ePUCCH, ePUSCH,
or eSR.
[0018] In some examples, each communication link 125 may include one or more carriers, where
each carrier may be a signal made up of multiple sub-carriers (
e.g., waveform signals of different frequencies) modulated according to the various radio
technologies described above. Each modulated signal may be sent on a different sub-carrier
and may carry control information (
e.g., reference signals, control channels,
etc.)
, overhead information, user data,
etc. The communication links 125 may transmit bidirectional communications using a frequency
domain duplexing (FDD) operation (
e.g., using paired spectrum resources) or a time domain duplexing (TDD) operation (
e.g., using unpaired spectrum resources). Frame structures for FDD operation (
e.g., frame structure type 1) and TDD operation (
e.g., frame structure type 2) may be defined.
[0019] In some examples of the wireless communication system 100, base stations 105 or UEs
115 may include multiple antennas for employing antenna diversity schemes to improve
communication quality and reliability between base stations 105 and UEs 115. Additionally
or alternatively, base stations 105 or UEs 115 may employ multiple-input, multiple-output
(MIMO) techniques that may take advantage of multi-path environments to transmit multiple
spatial layers carrying the same or different coded data.
[0020] The wireless communication system 100 may support operation on multiple cells or
carriers, a feature which may be referred to as carrier aggregation (CA) or dual-connectivity
operation. A carrier may also be referred to as a component carrier (CC), a layer,
a channel,
etc. The terms "carrier," "component carrier," "cell," and "channel" may be used interchangeably
herein. A UE 115 may be configured with multiple downlink CCs and one or more uplink
CCs for carrier aggregation. Carrier aggregation may be used with both FDD and TDD
component carriers.
[0021] In an LTE/LTE-A network, a UE 115 may be configured to communicate using up to five
CCs when operating in a carrier aggregation mode or dual-connectivity mode. One or
more of the CCs may be configured as a DL CC, and one or more of the CCs may be configured
as a UL CC.
[0022] In some examples, the wireless communication system 100 may support operation over
a dedicated radio frequency spectrum band (
e.g., a radio frequency spectrum band for which transmitting apparatuses may not contend
for access because the radio frequency spectrum band is licensed to particular users
for particular uses, such as a licensed radio frequency spectrum band (
e.g., licensed spectrum) usable for LTE/LTE-A communications) or a shared radio frequency
spectrum band (
e.g., a radio frequency spectrum band for which transmitting apparatuses may need to contend
for access (
e.g., a radio frequency spectrum band (
e.g., unlicensed spectrum) that is available for unlicensed use, such as Wi-Fi use, or
a radio frequency spectrum band that is available for use by multiple operators in
an equally shared or prioritized manner)). The dedicated radio frequency spectrum
band or shared radio frequency spectrum band may be used for LTE/LTE-A communications.
[0023] With increasing data traffic in cellular networks that use a dedicated radio frequency
spectrum band, offloading of at least some data traffic to a shared radio frequency
spectrum band may provide a cellular operator (
e.g., an operator of a public land mobile network (PLMN) or a coordinated set of base stations
defining a cellular network, such as an LTE/LTE-A network) with opportunities for
enhanced data transmission capacity. Use of a shared radio frequency spectrum band
may also provide service in areas where access to a dedicated radio frequency spectrum
band is unavailable. Before communicating over a shared radio frequency spectrum band,
transmitting apparatuses may perform a listen before talk (LBT) procedure to gain
access to the shared radio frequency spectrum band. Such an LBT procedure may include
performing a clear channel assessment (CCA) procedure (or an extended CCA procedure)
to determine whether a channel of the shared radio frequency spectrum band is available.
When it is determined that the channel of the shared radio frequency spectrum band
is available, a channel reservation signal (
e.g., a channel usage beacon signal (CUBS)) may be transmitted to reserve the channel.
The channel reservation signal may reserve the shared radio frequency spectrum by
providing a detectable energy on the shared radio frequency spectrum band. The channel
reservation signal may also serve to identify the transmitting apparatus or synchronize
the transmitting apparatus and a receiving apparatus. When it is determined that a
channel is not available, a CCA procedure (or extended CCA procedure) may be performed
for the channel again at a later time.
[0024] After a UE 115 wins contention for access to a shared radio frequency spectrum band,
the UE 115 may communicate with a base station 105 on an uplink. In some examples,
the UE 115 may communicate on the uplink in an uplink carrier aggregation mode or
a dual-connectivity mode. When the UE 115 is also communicating with the base station
105 using at least one UL CC in a dedicated radio frequency spectrum band and at least
one UL CC in the shared radio frequency spectrum band, the UE 115 may have to select
a UL CC in the dedicated radio frequency spectrum band and/or a UL CC in the shared
radio frequency spectrum band for transmitting UCI. In some scenarios, a UL CC in
the dedicated radio frequency spectrum band may be more reliable than a UL CC in the
shared radio frequency spectrum band, and it may be useful to configure or bias the
UE to select a UL CC in the dedicated radio frequency spectrum band for transmitting
UCI (
e.g., one or more of an SR, an ACK/non-acknowledgement (NAK), periodic channel state information
(CSI), or aperiodic CSI).
[0025] FIG. 2 shows a wireless communication system 200 in which LTE/LTE-A may be deployed under
different scenarios using a dedicated radio frequency spectrum band or a shared radio
frequency spectrum band, in accordance with various aspects of the present disclosure.
More specifically, FIG. 2 illustrates examples of a supplemental downlink mode (also
referred to as a shared downlink mode), a carrier aggregation mode, and a standalone
mode in which LTE/LTE-A is deployed using a shared radio frequency spectrum band.
The wireless communication system 200 may be an example of portions of the wireless
communication system 100 described with reference to FIG. 1. Moreover, a first base
station 205 and a second base station 205-a may be examples of aspects of one or more
of the base stations 105 described with reference to FIG. 1, while a first UE 215,
a second UE 215-a, a third UE 215-b, and a fourth UE 215-c may be examples of aspects
of one or more of the UEs 115 described with reference to FIG. 1.
[0026] In the example of a supplemental downlink mode in the wireless communication system
200, the first base station 205 may transmit OFDMA waveforms to the first UE 215 using
a downlink channel 220. The downlink channel 220 may be associated with a frequency
F1 in a shared radio frequency spectrum band. The first base station 205 may transmit
OFDMA waveforms to the first UE 215 using a first bidirectional link 225 and may receive
SC-FDMA waveforms from the first UE 215 using the first bidirectional link 225. The
first bidirectional link 225 may be associated with a frequency F4 in a dedicated
radio frequency spectrum band. The downlink channel 220 in the shared radio frequency
spectrum band and the first bidirectional link 225 in the dedicated radio frequency
spectrum band may operate contemporaneously. The downlink channel 220 may provide
a downlink capacity offload for the first base station 205. In some examples, the
downlink channel 220 may be used for unicast services (
e.g., addressed to one UE) or for multicast services (
e.g., addressed to several UEs). This scenario may occur with any service provider (
e.g., a mobile network operator (MNO)) that uses a dedicated radio frequency spectrum and
needs to relieve some of the traffic or signaling congestion.
[0027] In one example of a carrier aggregation mode in the wireless communication system
200, the first base station 205 may transmit OFDMA waveforms to the second UE 215-a
using a second bidirectional link 230 and may receive OFDMA waveforms, SC-FDMA waveforms,
or resource block interleaved FDMA waveforms from the second UE 215-a using the second
bidirectional link 230. The second bidirectional link 230 may be associated with the
frequency F1 in the shared radio frequency spectrum band. The first base station 205
may also transmit OFDMA waveforms to the second UE 215-a using a third bidirectional
link 235 and may receive SC-FDMA waveforms from the second UE 215-a using the third
bidirectional link 235. The third bidirectional link 235 may be associated with a
frequency F2 in a dedicated radio frequency spectrum band. The second bidirectional
link 230 may provide a downlink and uplink capacity offload for the first base station
205. Like the supplemental downlink described above, this scenario may occur with
any service provider (
e.g., MNO) that uses a dedicated radio frequency spectrum and needs to relieve some of
the traffic or signaling congestion.
[0028] In another example of a carrier aggregation mode in the wireless communication system
200, the first base station 205 may transmit OFDMA waveforms to the third UE 215-b
using a fourth bidirectional link 240 and may receive OFDMA waveforms, SC-FDMA waveforms,
or resource block interleaved waveforms from the third UE 215-b using the fourth bidirectional
link 240. The fourth bidirectional link 240 may be associated with a frequency F3
in the shared radio frequency spectrum band. The first base station 205 may also transmit
OFDMA waveforms to the third UE 215-b using a fifth bidirectional link 245 and may
receive SC-FDMA waveforms from the third UE 215-b using the fifth bidirectional link
245. The fifth bidirectional link 245 may be associated with the frequency F2 in the
dedicated radio frequency spectrum band. The fourth bidirectional link 240 may provide
a downlink and uplink capacity offload for the first base station 205. This example
and those provided above are presented for illustrative purposes and there may be
other similar modes of operation or deployment scenarios that combine LTE/LTE-A in
a dedicated radio frequency spectrum band and use a shared radio frequency spectrum
band for capacity offload.
[0029] As described above, one type of service provider that may benefit from the capacity
offload offered by using LTE/LTE-A in a shared radio frequency spectrum band is a
traditional MNO having access rights to an LTE/LTE-A dedicated radio frequency spectrum
band. For these service providers, an operational example may include a bootstrapped
mode (
e.g., supplemental downlink, carrier aggregation) that uses the LTE/LTE-A primary component
carrier (PCC, or PCell) on the dedicated radio frequency spectrum band and at least
one secondary component carrier (SCC, or SCell) on the shared radio frequency spectrum
band.
[0030] In the carrier aggregation mode, data and control may, for example, be communicated
in the dedicated radio frequency spectrum band (
e.g., via first bidirectional link 225, third bidirectional link 235, and fifth bidirectional
link 245) while data may, for example, be communicated in the shared radio frequency
spectrum band (
e.g., via second bidirectional link 230 and fourth bidirectional link 240). The carrier
aggregation mechanisms supported when using a shared radio frequency spectrum band
may fall under a hybrid frequency division duplexing-time division duplexing (FDD-TDD)
carrier aggregation or a TDD-TDD carrier aggregation with different symmetry across
component carriers.
[0031] In one example of a standalone mode in the wireless communication system 200, the
second base station 205-a may transmit OFDMA waveforms to the fourth UE 215-c using
a bidirectional link 250 and may receive OFDMA waveforms, SC-FDMA waveforms, or resource
block interleaved FDMA waveforms from the fourth UE 215-c using the bidirectional
link 250. The bidirectional link 250 may be associated with the frequency F3 in the
shared radio frequency spectrum band. The standalone mode may be used in non-traditional
wireless access scenarios, such as in-stadium access (
e.g., unicast, multicast). An example of a type of service provider for this mode of operation
may be a stadium owner, cable company, event host, hotel, enterprise, or large corporation
that does not have access to a dedicated radio frequency spectrum band.
[0032] In some examples, a transmitting apparatus such as one of the base stations 105,
205, or 205-a described with reference to FIG. 1 or 2, or one of the UEs 115, 215,
215-a, 215-b, or 215-c described with reference to FIG. 1 or 2, may use a gating interval
to gain access to a channel of a shared radio frequency spectrum band (
e.g., to a physical channel of the shared radio frequency spectrum band). In some examples,
the gating interval may be periodic. For example, the periodic gating interval may
be synchronized with at least one boundary of an LTE/LTE-A radio interval. The gating
interval may define the application of a contention-based protocol, such as an LBT
protocol based on the LBT protocol specified in European Telecommunications Standards
Institute (ETSI) (EN 301 893). When using a gating interval that defines the application
of an LBT protocol, the gating interval may indicate when a transmitting apparatus
needs to perform a contention procedure (
e.g., an LBT procedure) such as a clear channel assessment (CCA) procedure. The outcome
of the CCA procedure may indicate to the transmitting apparatus whether a channel
of a shared radio frequency spectrum band is available or in use for the gating interval
(also referred to as an LBT radio frame). When a CCA procedure indicates that the
channel is available for a corresponding LBT radio frame (
e.g., "clear" for use), the transmitting apparatus may reserve or use the channel of the
shared radio frequency spectrum band during part or all of the LBT radio frame. When
the CCA procedure indicates that the channel is not available (
e.g., that the channel is in use or reserved by another transmitting apparatus), the transmitting
apparatus may be prevented from using the channel during the LBT radio frame.
[0033] FIG. 3 shows an example 300 of a wireless communication 310 over a shared radio frequency
spectrum band, in accordance with various aspects of the present disclosure. In some
examples, the wireless communication 310 may include a transmission of one or more
uplink component carriers, which uplink component carrier(s) may be transmitted, for
example, as part of a transmission made according to the supplemental downlink mode,
the carrier aggregation mode, or the standalone mode described with reference to FIG.
2, the carrier aggregation mode described with reference to FIG. 5, and/or the dual-connectivity
mode described with referenced to FIG. 6.
[0034] In some examples, an LBT radio frame 315 of the wireless communication 310 may have
a duration often milliseconds and include a number of downlink (D) subframes 320,
a number of uplink (U) subframes 325, and two types of special subframes, an S subframe
330 and an S' subframe 335. The S subframe 330 may provide a transition between downlink
subframes 320 and uplink subframes 325, while the S' subframe 335 may provide a transition
between uplink subframes 325 and downlink subframes 320 and, in some examples, a transition
between LBT radio frames.
[0035] During the S' subframe 335, a downlink clear channel assessment (DCCA) procedure
345 may be performed by one or more base stations, such as one or more of the base
stations 105, 205, or 205-a described with reference to FIG. 1 or 2, to reserve, for
a period of time, a channel of the shared radio frequency spectrum band over which
the wireless communication 310 occurs. Following a successful DCCA procedure 345 by
a base station, the base station may transmit a channel usage beacon signal (CUBS)
(
e.g., a downlink CUBS (D-CUBS 350)) to provide an indication to other base stations or
apparatuses (
e.g., UEs, Wi-Fi access points,
etc.) that the base station has reserved the channel. In some examples, a D-CUBS 350 may
be transmitted using a plurality of interleaved resource blocks. Transmitting a D-CUBS
350 in this manner may enable the D-CUBS 350 to occupy at least a certain percentage
of the available frequency bandwidth of the shared radio frequency spectrum band and
satisfy one or more regulatory requirements (
e.g., a requirement that transmissions over the shared radio frequency spectrum band occupy
at least 80% of the available frequency bandwidth). The D-CUBS 350 may in some examples
take a form similar to that of an LTE/LTE-A common reference signal (CRS) or a channel
state information reference signal (CSI-RS). When the DCCA procedure 345 fails, the
D-CUBS 350 may not be transmitted.
[0036] The S' subframe 335 may include a plurality of OFDM symbol periods (
e.g., 14 OFDM symbol periods). A first portion of the S' subframe 335 may be used by a
number of UEs as a shortened uplink (U) period. A second portion of the S' subframe
335 may be used for the DCCA procedure 345. A third portion of the S' subframe 335
may be used by one or more base stations that successfully contend for access to the
channel of the shared radio frequency spectrum band to transmit the D-CUBS 350.
[0037] During the S subframe 330, an uplink CCA (UCCA) procedure 365 may be performed by
one or more UEs, such as one or more of the UEs 115, 215, 215-a, 215-b, or 215-c described
above with reference to FIG. 1 or 2, to reserve, for a period of time, the channel
over which the wireless communication 310 occurs. Following a successful UCCA procedure
365 by a UE, the UE may transmit an uplink CUBS (U-CUBS 370) to provide an indication
to other UEs or apparatuses (
e.g., base stations, Wi-Fi access points,
etc.) that the UE has reserved the channel. In some examples, a U-CUBS 370 may be transmitted
using a plurality of interleaved resource blocks. Transmitting a U-CUBS 370 in this
manner may enable the U-CUBS 370 to occupy at least a certain percentage of the available
frequency bandwidth of the shared radio frequency spectrum band and satisfy one or
more regulatory requirements (
e.g., the requirement that transmissions over the shared radio frequency spectrum band
occupy at least 80% of the available frequency bandwidth). The U-CUBS 370 may in some
examples take a form similar to that of an LTE/LTE-A CRS or CSI-RS. When the UCCA
procedure 365 fails, the U-CUBS 370 may not be transmitted.
[0038] The S subframe 330 may include a plurality of OFDM symbol periods (
e.g., 14 OFDM symbol periods). A first portion of the S subframe 330 may be used by a number
of base stations as a shortened downlink (D) period 355. A second portion of the S
subframe 330 may be used as a guard period (GP) 360. A third portion of the S subframe
330 may be used for the UCCA procedure 365. A fourth portion of the S subframe 330
may be used by one or more UEs that successfully contend for access to the channel
of the shared radio frequency spectrum band as an uplink pilot time slot (UpPTS) or
to transmit the U-CUBS 370.
[0039] In some examples, the DCCA procedure 345 or the UCCA procedure 365 may include the
performance of a single CCA procedure. In other examples, the DCCA procedure 345 or
the UCCA procedure 365 may include the performance of an extended CCA procedure. The
extended CCA procedure may include a random number of CCA procedures, and in some
examples may include a plurality of CCA procedures.
[0040] FIG. 4 shows a wireless communication system 400 in which LTE/LTE-A may be deployed under
different scenarios using a dedicated radio frequency spectrum band or a shared radio
frequency spectrum band, in accordance with various aspects of the present disclosure.
The wireless communication system 400 may be an example of portions of the wireless
communication system 100 or 200 described with reference to FIG. 1 or 2. Moreover,
a first base station 405 and a second base station 405-a may be examples of aspects
of one or more of the base stations 105, 205, or 205-a described with reference to
FIG. 1 or 2, while a first UE 415 and a second UE 415-a may be examples of aspects
of one or more of the UEs 115, 215, 215-a, 215-b, or 215-c described with reference
to FIG. 1 or 2.
[0041] In the wireless communication system 400, the base station 405 may win contention
for access to a shared radio frequency spectrum band and begin communicating with
the UE 415 via communication link 425. However, communications with the UE may experience
interference as a result of the UE 415-a communicating with the base station 405-a.
When the base station 405 contends for access to the shared radio frequency spectrum
band (
e.g., performs a DCCA procedure) while the base station 405-a is communicating with the
UE 415-a on downlink, the base station 405 may not detect the energy of the communications
on the shared radio frequency spectrum band because the base station 405-a operates
outside the coverage area 410 of the base station 405. Similarly, if the UE 415-a
contends for access to the shared radio frequency spectrum band (
e.g., performs a UCCA procedure) while the base station 405 is communicating with the UE
415 on downlink, the UE 415-a may not detect the energy of the communications on the
shared radio frequency spectrum band because the base station 405 operates outside
the coverage area of the UE 415-a. The UE 415 may also contend for access to the shared
radio frequency spectrum band (
e.g., perform a UCCA procedure) while the base station 405-a is communicating with the
UE 415-a on downlink, and thus not detect the energy of the communications on the
shared radio frequency spectrum band because the base station 405-a operates outside
the coverage area of the UE 415. Scenarios may therefore arise when communications
over the communication link 425 experience hidden node interference (
i.e., interference from nodes, such as the UE 415-a, that are able to gain access to
the shared radio frequency spectrum band at the same time as the base station 405
or 415. The UE 415-a, which may operate as a hidden node to the base station 405,
may also prevent the UE 415 performing a successful UCCA, and thereby prevent the
UE 415 from communicating with the base station 405 over an uplink (
e.g., to transmit UCI to the base station 405).
[0042] FIG. 5 shows a wireless communication system 500 in which LTE/LTE-A may be deployed in a
carrier aggregation scenario, in accordance with various aspects of the present disclosure.
The wireless communication system 500 may be an example of portions of the wireless
communication system 100, 200, or 400 described with reference to FIG. 1, 2, or 4.
Moreover, a base station 505 may be an example of aspects of one or more of the base
stations 105, 205, 205-a, 405, or 405-a described with reference to FIG. 1, 2, or
4, while a UE 515 may be an examples of aspects of one or more of the UEs 115, 215,
215-a, 215-b, 215-c, 415, or 415-a described with reference to FIG. 1, 2, or 4.
[0043] When communicating in a carrier aggregation mode using LTE/LTE-A communications,
the UE 515 may communicate with the base station 505 using up to five component carriers
(CCs). Each of the CCs may have a bandwidth of up to 20MHz (e.g., the UE 515 may component
with the base station 505 over a 100MHz bandwidth). The CCs may all operate in an
FDD mode, all operate in a TDD mode, or operate in a mixture of FDD and TDD modes.
Different CCs may have the same or different DL/UL configurations (and special subframes
may be configured differently for different TDD CCs). When communicating in an enhanced
carrier aggregation (eCA) mode, the UE 515 may communicate with the base station 505
using up to 32 CCs. One of the CCs may be designated as a primary CC, and the remaining
CCs may be designated as secondary CCs. In some examples, the primary CC may carry
a PUCCH and common search space for the UE 515. In other examples, the primary CC
and one or more secondary CCs may each carry a PUCCH (
e.g., for load balancing). In some cases, each PUCCH may carry UCI. Each CC may be configured
as a DL CC, a UL CC, or a cell (
e.g., a CC that may be configured for use as a DL CC and/or a UL CC). By way of example,
FIG. 5 illustrates communication between the UE 515 and the base station 505 over
five CCs, including a first CC 520, a second CC 525, a third CC 530, a fourth CC 535,
and a fifth CC 540. Each of the first CC 520, the second CC 525, the third CC 530,
the fourth CC 535, and the fifth CC 540 may operate in a dedicated radio frequency
spectrum band or a shared radio frequency spectrum band, depending on how the CC is
allocated or configured.
[0044] When the UE 515 is configured for operation in a supplemental downlink mode of operation
using a shared radio frequency spectrum band, as described with reference to FIG.
2, and when the UE 515 is operating in a carrier aggregation mode, one or more of
the first CC 520, the second CC 525, the third CC 530, the fourth CC 535, or the fifth
CC 540 may operate as a UL CC or a DL CC in the dedicated radio frequency spectrum
band, and one or more of the first CC 520, the second CC 525, the third CC 530, the
fourth CC 535, or the fifth CC 540 may operate as a DL CC in the shared radio frequency
spectrum band.
[0045] When the UE 515 is configured for operation in a carrier aggregation mode of operation
using the shared radio frequency spectrum band, as described with reference to FIG.
2, one or more of the first CC 520, the second CC 525, the third CC 530, the fourth
CC 535, or the fifth CC 540 may operate as a UL CC or a DL CC in the dedicated radio
frequency spectrum band, and one or more of the first CC 520, the second CC 525, the
third CC 530, the fourth CC 535, or the fifth CC 540 may operate as a DL CC or a UL
CC in the shared radio frequency spectrum band. In some examples, all of the DL CCs
may operate in the dedicated radio frequency spectrum band, or all of the UL CCs may
operate in the shared radio frequency spectrum band, but not all of the DL CCs and
all of the UL CCs may operate in the shared radio frequency spectrum band (
e.g., at least one DL CC or at least UL CC operates in the dedicated radio frequency spectrum
band).
[0046] When the UE 515 is configured for operation in a standalone mode of operation using
the shared radio frequency spectrum band, as described with reference to FIG. 2, and
when the UE 515 is operating in a carrier aggregation mode, each of the first CC 520,
the second CC 525, the third CC 530, the fourth CC 535, and the fifth CC 540 may operate
in the shared radio frequency spectrum band.
[0047] FIG. 6 shows a wireless communication system 600 in which LTE/LTE-A may be deployed in a
dual-connectivity scenario (
e.g., a coordinated multipoint (CoMP) scenario), in accordance with various aspects of
the present disclosure. The wireless communication system 600 may be an example of
portions of the wireless communication system 100, 200, 400, or 500 described with
reference to FIG. 1, 2, 4, or 5. Moreover, a first base station 605 and a second base
station 605-a may be examples of aspects of one or more of the base stations 105,
205, 205-a, 405, 405-a, or 505 described with reference to FIG. 1, 2, 4, or 5, while
a UE 615 may be an examples of aspects of one or more of the UEs 115, 215, 215-a,
215-b, 215-c, 415, 415-a, or 515 described with reference to FIG. 1, 2, 4, or 5. The
first base station 605 and the second base station 605-a may or may not be connected
by an ideal backhaul. When the first base station 605 and the second base station
605-a are not connected by an ideal backhaul, there may be loose coordination between
the base stations (
e.g., as a result of limited backhaul capacity or non-negligible backhaul latency (
e.g., tens of milliseconds)).
[0048] When communicating in a dual-connectivity mode using LTE/LTE-A communications, the
UE 615 may communicate with multiple base stations, such as the first base station
605 and the second base station 605-a,using, for example, five or more CCs. One of
the CCs may be designated as a primary CC, and the remaining CCs may be designated
as secondary CCs. Each CC may be configured as a DL CC, a UL CC, or a cell (
e.g., a CC that may be configured for use as a DL CC and/or a UL CC). By way of example,
FIG. 5 illustrates communication between the UE 615 and the base station 605 over
three CCs, including a first CC 620, a second CC 625, and a third CC 630. In some
examples, the first CC 620 and the second CC 625 (in communication with the first
base station 605) may be configured as a primary group of CCs 635 in a dual-connectivity
operation, and the third CC 630 (in communication with the second base station 505-a)
may be configured as a secondary group of CCs 640 in the dual-connectivity operation.
The first CC 620, the second CC 625, and the third CC 630 may be configured for various
modes of operation using a dedicated radio frequency spectrum band or a shared radio
frequency spectrum band, similarly to how component carriers may be used in a carrier
aggregation mode of operation, as described, for example, with reference to FIG. 5.
[0049] In some examples, a first PUCCH may be carried by a CC in the primary group of CCs
635 and a second PUCCH may be carried by a CC in the secondary group of CCs 640, such
that UCI may be separately conveyed to each of the primary group of CCs 635 and the
secondary group of CCs 640. In some examples, a PUCCH may be carried by each of the
CCs in each of the primary group of CCs 635 and the secondary group of CCs 640, and
in some examples, each PUCCH may carry UCI. The UE 615 may also monitor a common search
space of the primary group of CCs 635 and a common search space of the secondary group
of CCs 640. Semi-persistent scheduling (SPS) and scheduling request (SR) transmission
may also be supported by each of the primary group of CCs 635 and the secondary group
of CCs 640.
[0050] Various types of UCI, including ACK/NAK information, an SR, or CSI may be transmitted
on a UL CC. In some examples, the various types of UCI may have different performance
targets (or requirements). For example, ACK/NAK information may have the highest performance
target (
e.g., NAK to ACK error rate may be on the order of 10
-3 or less), SR may have a next highest performance target, and a performance target
higher than that of CSI; and CSI may be able to tolerate reasonable performance degradation
(
e.g., CSI may be associated with a 4% bit error rate (BER) performance target). In general,
transmission of UCI over a shared radio frequency spectrum band is less reliable than
transmission of UCI over a dedicated radio frequency spectrum band, because of the
potential for hidden node interference, as described with reference to FIG. 4.
[0051] When UCI is transmitted on a PUSCH (
i.e., piggybacked on a PUSCH), it can be difficult to ensure UCI performance targets are
met while also maintaining efficient UL operation. To help ensure that UCI performance
targets are met, the amount of resources allocated for UCI on a PUSCH may be allocated
conservatively. In part because of the conservative allocation of resources for UCI
on a PUSCH, ACK/NAK information transmitted on a PUSCH is currently not protected
by a CRC. ACK/NAK information transmitted on a PUCCH is also not currently protected
by a CRC. However, when a PUCCH is associated with an eCA mode of operation (
e.g., associated with up to 32 CCs), or when a PUCCH is associated with a CC transmitted
in a shared radio frequency spectrum band, the protection of ACK/NAK information by
a CRC may be useful. The protection of ACK/NAK information by a CRC can enable better
NAK to ACK error management (
e.g., the protection of ACK/NAK information by a 16-bit CRC may reduce the NAK to ACK error
from approximately 10
-3 to 10
-5).
[0052] When ACK/NAK information is carried on a PUCCH, protection of the ACK/NAK information
by a CRC may be conditioned on various factors. For example, the decision to protect
ACK/NAK information by a CRC may be based on the PUCCH format on which the ACK/NAK
information is transmitted (
e.g., ACK/NAK information transmitted on PUCCH format 3 may not be protected by a CRC,
but ACK/NAK information transmitted on PUCCH format 4 may be protected by a CRC).
As another example, the decision to protect ACK/NAK information by a CRC may be based
on a payload size. The decision to protect ACK/NAK information by a CRC may also be
based on a payload size in combination with the PUCCH format on which the ACK/NAK
information is transmitted. For example, ACK/NAK information transmitted on PUCCH
format 3 may not be protected by a CRC, but ACK/NAK information transmitted on PUCCH
format 4 may or may not be protected by a CRC, depending on the payload size (e.g.,
when the payload size ≥ a payload size threshold, ACK/NAK information transmitted
on PUCCH format 4 may be protected by a CRC, and when the payload size < the payload
size threshold, ACK/NAK information transmitted on PUCCH format 4 may not be protected
by a CRC). By way of example, the payload size threshold may be 10 bits.
[0053] The payload size used to determine whether ACK/NAK information should be protected
by a CRC may be based on any combination of ACK/NAK, SR, and CSI information transmitted
on a PUCCH. For example, when ACK/NAK/SR information and CSI information are jointly
coded, the transmission of ACK/NAK information on PUCCH format 4 may be protected
by a CRC when an ACK/NAK/SR payload size ≥ a first payload size threshold, and the
transmission of ACK/NAK information on PUCCH format 4 may not be protected by a CRC
when the ACK/NAK/SR payload size < the first payload size threshold.
[0054] In some cases, LTE/LTE-A standards indicate (or suggest) that UCI should be transmitted
on a cell in a shared radio frequency spectrum band. For example, when aperiodic CSI
is triggered in a UL grant for a cell, LTE/LTE-A standards indicate that a PUSCH transmitted
on the cell should carry all of the UCI in a subframe. However, when the cell is in
the shared radio frequency spectrum band, the PUSCH transmitted on the cell may be
subject to hidden node interference, as described with reference to FIG. 4. Transmission
of the PUSCH, including the UCI, may therefore be less reliable than transmission
of a PUSCH (and UCI) on a cell in a dedicated radio frequency spectrum band. One way
to address the questionable reliability of the transmitting UCI in the shared radio
frequency spectrum band is to transmit all UCI on a cell in the dedicated radio frequency
spectrum band (
e.g., even when aperiodic CSI is triggered on a cell in the shared radio frequency spectrum
band). Alternatively, CSI may be transmitted on the PUSCH on the cell in the shared
radio frequency spectrum band, and ACK/NAK/SR or other information may be transmitted
(
e.g., piggybacked) on the cell in the dedicated radio frequency spectrum band.
[0055] When ACK/NAK information is transmitted during operation in an eCA mode, the ACK/NAK
information may be carried on a PUCCH, as previously described, or on a PUSCH (
e.g., as previously described).
[0056] Although ACK/NAK/SR information and CSI information is jointly coded when transmitted
on a PUCCH, ACK/NAK information, CQI/PMI information, and RI/payload transaction identifier
(PTI) information are separately coded and mapped on a PUSCH. When ACK/NAK information,
CQI/PMI information, and RI/PTI information are transmitted on a PUSCH, and are separately
coded, separate decisions may be made to protect the ACK/NAK information, CQI/PMI
information, and RI/PTI information by a CRC. For example, the decision to protect
the ACK/NAK information by a CRC may be based at least in part on a determined ACK/NAK
payload size (
e.g., similarly to the described decision process for protecting ACK/NAK information transmitted
on a PUCCH by a CRC). The same or different payload size thresholds may be used for
deciding whether to protect ACK/NAK information transmitted on a PUCCH and deciding
whether to protect ACK/NAK information transmitted on a PUSCH. Different payload size
thresholds may be useful when UCI transmitted on the PUCCH is jointly coded for different
UCI types (and when UCI transmitted on the PUSCH is separately coded). In some examples,
an ACK/NAK payload size may be determined based at least in part on a RRC configuration,
a dynamic indication, a detected number of transport blocks, or a combination thereof.
In some examples, the CRC used to protect ACK/NAK information transmitted on a PUSCH
may have a length of 16 bits.
[0057] In some examples, the decision to protect CQI/PMI information by a CRC, when transmitted
on a PUSCH, may be based on a CQI/PMI payload size. For example, when the CQI/PMI
payload size is greater than 11 bits, the CQI/PMI information may be protected by
a CRC, and when the CQI/PMI payload size is less than or equal to 11 bits, the CQI/PMI
information may not be protected by a CRC. In some examples, the CRC used to protect
CQI/PMI information transmitted on a PUSCH may have a length of 8 bits.
[0058] In some examples, the decision to protect RI/PTI information by a CRC, when transmitted
on a PUCCH, may be based on an RI/PTI payload size or a number of CCs for which RI/PTI
information is reported. For example, when the RI/PTI payload size is greater than
11 bits, the RI/PTI information may be protected by a CRC, and when the RI/PTI payload
size is less than or equal to 11 bits, the RI/PTI information may not be protected
by a CRC. Alternatively, when RI/PTI information is reported for two or more CCs,
the RI/PTI information may be protected by a CRC, and when the RI/PTI information
is reported for one CC, the RI/PTI information may not be protected by a CRC. In some
examples, the CRC used to protect RI/PTI information transmitted on a PUSCH may have
a length of 8 bits.
[0059] FIG. 7 shows a block diagram of a wireless device 700 configured to transmit a CRC for UCI
on control and data channels in accordance with various aspects of the present disclosure.
Wireless device 700 may be an example of aspects of a UE 115, 215, 215-a, 215-b, 215-c,
415, 415-a, 515, or 615 described with reference to FIG. 1, 2, 4, 5, or 6. Wireless
device 700 may include a receiver 705, a CRC manager 710, or a transmitter 715. Wireless
device 700 may also include a processor. Each of these components may be in communication
with each other.
[0060] The receiver 705 may receive information such as packets, user data, or control information
associated with various information channels (
e.g., control channels, data channels, and information related to CRC for UCI on control
and data channels,
etc.)
. Information may be passed on to the CRC manager 710, and to other components of wireless
device 700.
[0061] The CRC manager 710 may identify UCI for a CC of a CA configuration that may include
a PCell and, in some aspects, a PUCCH enabled SCell, determine to include CRC information
for the UCI based at least in part on a UCI characteristic or an uplink control channel
format, and transmit an uplink channel including the UCI and the CRC information.
[0062] The transmitter 715 may transmit signals received from other components of wireless
device 700. In some examples, the transmitter 715 may be collocated with the receiver
705 in a transceiver module. The transmitter 715 may include a single antenna, or
it may include a plurality of antennas.
[0063] FIG. 8 shows a block diagram of a wireless device 800 to transmit a CRC for UCI on control
and data channels in accordance with various aspects of the present disclosure. Wireless
device 800 may be an example of aspects of a UE 115, 215, 215-a, 215-b, 215-c, 415,
415-a, 515, or 615 described with reference to FIG. 1, 2, 4, 5, or 6, or aspects of
the wireless device 700 described with reference to FIG. 7. Wireless device 800 may
include a receiver 705-a, a CRC manager 710-a, or a transmitter 715-a. Wireless device
800 may also include a processor. Each of these components may be in communication
with each other. The CRC manager 710-a may also include a UCI identification module
805, a CRC determination module 810, and an uplink channel transmission module 815.
[0064] The receiver 705-a may receive information which may be passed on to CRC manager
710-a, and to other components of wireless device 800. The CRC manager 710-a may perform
the operations described with reference to FIG. 7. The transmitter 715-a may transmit
signals received from other components of wireless device 800.
[0065] The UCI identification module 805 may identify UCI for a CC of a CA configuration
that may include a PCell and, in some aspects, a PUCCH enabled SCell as described,
for example, with reference to FIG. 5 or 6. In some examples, identifying UCI for
the CC of the CA configuration may include identifying UCI for a plurality of CCs
of the CA configuration, wherein the determination to include CRC information may
be based at least in part on a quantity of CCs in the plurality. In some examples,
the UCI characteristic may include a UCI type. In some examples, the UCI may include
a plurality of UCI types.
[0066] The CRC determination module 810 may determine to include CRC information for the
UCI based at least in part on a UCI characteristic or an uplink control channel format
as described, for example, with reference to FIG. 5 or 6. In some examples, the determination
to include CRC information may include determining whether to include CRC information
for each UCI type of the plurality. In some examples, the CRC information may include
a number bits that may be based at least in part on a UCI type.
[0067] The uplink channel transmission module 815 may transmit an uplink channel including
the UCI and the CRC information as described, for example, with reference to FIG.
5 or 6. In some examples, the threshold may be based at least in part on whether the
uplink channel includes a PUCCH or a PUSCH. In some examples, the uplink channel may
include a PUCCH or a PUSCH on the PCell. In some examples, the uplink channel may
include a PUCCH or a PUSCH on the PUCCH enabled SCell. In some examples, the CA configuration
may include more than five CCs.
[0068] FIG. 9 shows a block diagram 900 of a CRC manager 710-b which may be a component of the
wireless device 700 or the wireless device 800 in accordance with various aspects
of the present disclosure. The CRC manager 710-b may be an example of aspects of the
CRC manager 710 described with reference to FIG. 7 or 8. The CRC manager 710-b may
include a UCI identification module 805-a, a CRC determination module 810-a, and an
uplink channel transmission module 815-a. Each of these modules may perform the functions
described with reference to FIG. 8. The CRC manager 710-b may also include a spectrum
determination module 905, a UCI characteristic module 910, and a UCI encoding module
915.
[0069] The spectrum determination module 905 may determine that the CC includes frequency
resources of unlicensed spectrum. The determination to include CRC information for
the UCI may be based at least in part on the determination that the carrier includes
the frequency resources of the unlicensed spectrum as described, for example, with
reference to FIG. 5 or 6.
[0070] The UCI characteristic module 910 may be configured such that the UCI characteristic
may include a payload size of the UCI as described, for example, with reference to
FIG. 5 or 6. The UCI characteristic module 910 may also identify a payload size of
the UCI. The determination to include the CRC information may be based at least in
part on the payload size exceeding a threshold (
e.g., a payload size threshold). In some examples, the payload size of the UCI may be identified
based at least in part on at least one of an RRC configuration, dynamic signaling,
or a number of transport blocks, or any combination thereof. In some examples, the
plurality of UCI types may include at least one of an ACK, a NAK, a CQI, a PMI, an
RI, a PTI, or any combination thereof.
[0071] The UCI encoding module 915 may select a coding scheme for the payload of the UCI.
The determination to include the CRC information may be based at least in part on
the coding scheme as described, for example, with reference to FIG. 5 or 6.
[0072] FIG. 10 shows a diagram of a system 1000 including a UE 115 configured to transmit a CRC
for UCI on control and data channels in accordance with various aspects of the present
disclosure. System 1000 may include UE 1015, which may be an example of aspects of
a UE 115, 215, 215-a, 215-b, 215-c, 415, 415-a, 515, or 615 described with reference
to FIGs. 1, 2 4, 5, or 6, or aspects of the wireless device 700 or wireless device
800 described with reference to FIG. 7, 8, or 9. UE 1015 may include a CRC manager
1010, which may be an example of the CRC manager 710 described with reference to FIG.
7, 8, or 9. UE 1015 may also include components for bi-directional voice and data
communications including components for transmitting communications and components
for receiving communications. For example, UE 1015 may communicate bi-directionally
with UE 1015-a or base station 1005
[0073] UE 1015 may also include a processor 1025, and memory 1030 (including software (SW))
1020, a transceiver 1035, and one or more antenna(s) 1040, each of which may communicate,
directly or indirectly, with one another (
e.g., via buses 1045). The transceiver 1035 may communicate bi-directionally, via the antenna(s)
1040 or wired or wireless links, with one or more networks, as described above. For
example, the transceiver 1035 may communicate bi-directionally with a base station
105 or another UE 115. The transceiver 1035 may include a modem to modulate the packets
and provide the modulated packets to the antenna(s) 1040 for transmission, and to
demodulate packets received from the antenna(s) 1040. While UE 1015 may include a
single antenna 1040, UE 1015 may also have multiple antennas 1040 capable of concurrently
transmitting or receiving multiple wireless transmissions.
[0074] The memory 1030 may include random access memory (RAM) and read only memory (ROM).
The memory 1030 may store computer-readable, computer-executable software/firmware
code 1020 including instructions that, when executed, cause the processor 1025 to
perform various functions described herein (
e.g., the transmission of CRC for UCI on control and data channels,
etc.)
. Alternatively, the software/firmware code 1020 may not be directly executable by
the processor 1025 but cause a computer (
e.g., when compiled and executed) to perform functions described herein. The processor
1025 may include an intelligent hardware device, (
e.g., a central processing unit (CPU), a microcontroller, an application specific integrated
circuit (ASIC),
etc.)
[0075] The components of UE 1015, wireless device 700, wireless device 800, or CRC manager
710 may, individually or collectively, be implemented with at least one ASIC adapted
to perform some or all of the applicable functions in hardware. Alternatively, the
functions may be performed by one or more other processing units (or cores), on at
least one IC. In other examples, other types of integrated circuits may be used (
e.g., Structured/Platform ASICs, a field programmable gate array (FPGA), or another semi-custom
IC), which may be programmed in any manner known in the art. The functions of each
unit may also be implemented, in whole or in part, with instructions embodied in a
memory, formatted to be executed by one or more general or application-specific processors.
[0076] FIG. 11 shows a flowchart illustrating a method 1100 to transmit a CRC for UCI on control
and data channels in accordance with various aspects of the present disclosure. The
operations of method 1100 may be implemented by a UE 115, 215, 215-a, 215-b, 215-c,
415, 415-a, 515, 615, or 1015 as described with reference to FIG. 1, 2, 4, 5, 6, or
10, or a wireless device 700 or 800 or its components as described with reference
to FIG. 7, 8, or 9. For example, the operations of method 1100 may be performed by
the CRC manager 710 as described with reference to FIG. 7, 8, 9, or 10. In some examples,
a UE may execute a set of codes to control the functional elements of the UE to perform
the functions described below. Additionally or alternatively, the UE may perform aspects
the functions described below using special-purpose hardware.
[0077] At block 1105, the UE 115 may identify UCI for a CC of a CA configuration as described,
for example, with reference to FIG. 5 or 6. In some cases, the CA configuration may
further include a PCell and/or a PUCCH enabled SCell. In certain examples, the operations
of block 1105 may be performed by the UCI identification module 805 as described with
reference to FIG. 8.
[0078] At block 1110, the UE 115 may determine to include CRC information for the UCI based
at least in part on a UCI characteristic or an uplink control channel format as described,
for example, with reference to FIG. 5 or 6. In certain examples, the operations of
block 1110 may be performed by the CRC determination module 810 as described with
reference to FIG. 8.
[0079] At block 1115, the UE 115 may transmit an uplink channel including the UCI and the
CRC information as described, for example, with reference to FIG. 5 or 6. In certain
examples, the operations of block 1115 may be performed by the uplink channel transmission
module 815 as described with reference to FIG. 8.
[0080] FIG. 12 shows a flowchart illustrating a method 1200 to transmit a CRC for UCI on control
and data channels in accordance with various aspects of the present disclosure. The
operations of method 1200 may be implemented by a UE 115, 215, 215-a, 215-b, 215-c,
415, 415-a, 515, 615, or 1015 as described with reference to FIG. 1, 2, 4, 5, 6, or
10, or a wireless device 700 or 800 or its components as described with reference
to FIG. 7, 8, or 9. For example, the operations of method 1200 may be performed by
the CRC manager 710 as described with reference to FIG. 7, 8, 9, or 10. In some examples,
a UE may execute a set of codes to control the functional elements of the UE to perform
the functions described below. Additionally or alternatively, the UE may perform aspects
the functions described below using special-purpose hardware. The method 1200 may
also incorporate aspects of method 1100 of FIG. 11.
[0081] At block 1205, the UE 115 may identify UCI for a CC of a CA as described, for example,
with reference to FIG. 5 or 6. In certain examples, the operations of block 1205 may
be performed by the UCI identification module 805 as described with reference to FIG.
8.
[0082] At block 1210, the UE 115 may determine to include CRC information for the UCI based
at least in part on a UCI characteristic or an uplink control channel format as described,
for example, with reference to FIG. 5 or 6. In certain examples, the operations of
block 1210 may be performed by the CRC determination module 810 as described with
reference to FIG. 8.
[0083] At block 1215, the UE 115 may transmit an uplink channel including the UCI and the
CRC information as described, for example, with reference to FIG. 5 or 6. In certain
examples, the operations of block 1215 may be performed by the uplink channel transmission
module 815 as described with reference to FIG. 8.
[0084] At block 1220, the UE 115 may determine that the CC includes frequency resources
of unlicensed spectrum. The determination to include CRC information for the UCI may
be based at least in part on the determination that the carrier includes the frequency
resources of the unlicensed spectrum as described, for example, with reference to
FIG. 5 or 6. In certain examples, the operations of block 1220 may be performed by
the spectrum determination module 905 as described with reference to FIG. 9.
[0085] FIG. 13 shows a flowchart illustrating a method 1300 to transmit a CRC for UCI on control
and data channels in accordance with various aspects of the present disclosure. The
operations of method 1300 may be implemented by a UE 115, 215, 215-a, 215-b, 215-c,
415, 415-a, 515, 615, or 1015 as described with reference to FIG. 1, 2, 4, 5, 6, or
10, or a wireless device 700 or 800 or its components as described with reference
to FIG. 7, 8, or 9. For example, the operations of method 1300 may be performed by
the CRC manager 710 as described with reference to FIG. 7, 8, 9, or 10. In some examples,
a UE may execute a set of codes to control the functional elements of the UE to perform
the functions described below. Additionally or alternatively, the UE may perform aspects
the functions described below using special-purpose hardware. The method 1300 may
also incorporate aspects of methods 1100, and 1200 of FIGs. 11-12.
[0086] At block 1305, the UE 115 may identify UCI for a CC of a CA as described, for example,
with reference to FIG. 5 or 6. In certain examples, the operations of block 1305 may
be performed by the UCI identification module 805 as described with reference to FIG.
8.
[0087] At block 1310, the UE 115 may determine to include CRC information for the UCI based
at least in part on a UCI characteristic or an uplink control channel format as described,
for example, with reference to FIG. 5 or 6. In some cases, the UCI characteristic
may include a payload size of the UCI. In certain examples, the operations of block
1310 may be performed by the CRC determination module 810 as described with reference
to FIG. 8.
[0088] At block 1315, the UE 115 may transmit an uplink channel including the UCI and the
CRC information as described, for example, with reference to FIG. 5 or 6. In certain
examples, the operations of block 1315 may be performed by the uplink channel transmission
module 815 as described with reference to FIG. 8.
[0089] At block 1320, the UE 115 may identify a payload size of the UCI. The determination
to include the CRC information may be based at least in part on the payload size exceeding
a threshold (
e.g., a payload size threshold) as described with reference to FIG. 5 or 6. In certain
examples, the operations of block 1320 may be performed by the UCI characteristic
module 910 as described with reference to FIG. 9.
[0090] FIG. 14 shows a flowchart illustrating a method 1400 to transmit a CRC for UCI on control
and data channels in accordance with various aspects of the present disclosure. The
operations of method 1400 may be implemented by a UE 115, 215, 215-a, 215-b, 215-c,
415, 415-a, 515, 615, or 1015 as described with reference to FIG. 1, 2, 4, 5, 6, or
10, or a wireless device 700 or 800 or its components as described with reference
to FIG. 7, 8, or 9. For example, the operations of method 1400 may be performed by
the CRC manager 710 as described with reference to FIG. 7, 8, 9, or 10. In some examples,
a UE may execute a set of codes to control the functional elements of the UE to perform
the functions described below. Additionally or alternatively, the UE may perform aspects
the functions described below using special-purpose hardware. The method 1400 may
also incorporate aspects of methods 1100, 1200, and 1300 of FIGs. 11-13.
[0091] At block 1405, the UE 115 may identify UCI for a CC of a CA configuration as described,
for example, with reference to FIG. 5 or 6. In certain examples, the operations of
block 1405 may be performed by the UCI identification module 805 as described with
reference to FIG. 8.
[0092] At block 1410, the UE 115 may determine to include CRC information for the UCI based
at least in part on a UCI characteristic or an uplink control channel format as described,
for example, with reference to FIG. 5 or 6. In some cases, the UCI characteristic
may include a payload size of the UCI. In certain examples, the operations of block
1410 may be performed by the CRC determination module 810 as described with reference
to FIG. 8.
[0093] At block 1415, the UE 115 may transmit an uplink channel including the UCI and the
CRC information as described, for example, with reference to FIG. 5 or 6. In certain
examples, the operations of block 1415 may be performed by the uplink channel transmission
module 815 as described with reference to FIG. 8.
[0094] At block 1420, the UE 115 may select a coding scheme for the payload of the UCI.
The determination to include the CRC information may be based at least in part on
the coding scheme as described, for example, with reference to FIG. 5 or 6. In certain
examples, the operations of block 1420 may be performed by the UCI encoding module
915 as described with reference to FIG. 9.
[0095] Thus, methods 1100, 1200, 1300, and 1400 may provide for transmitting a CRC for UCI
on control and data channels. It should be noted that methods 1100, 1200, 1300, and
1400 describe possible implementation, and that the operations and the steps may be
rearranged or otherwise modified such that other implementations are possible. In
some examples, aspects from two or more of the methods 1100, 1200, 1300, and 1400
may be combined.
[0096] Techniques described herein may be used for various wireless communications systems
such as code division multiple access (CDMA), time division multiple access (TDMA),
frequency division multiple access (FDMA), orthogonal frequency division multiple
access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and other
systems. The terms "system" and "network" are often used interchangeably. A code division
multiple access (CDMA) system may implement a radio technology such as CDMA2000, Universal
Terrestrial Radio Access (UTRA),
etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are
commonly referred to as CDMA2000 1X, 1X,
etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data
(HRPD),
etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A time division multiple
access (TDMA) system may implement a radio technology such as Global System for Mobile
Communications (GSM). An orthogonal frequency division multiple access (OFDMA) system
may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA
(E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM,
etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications system (UMTS). 3GPP
Long Term Evolution (LTE) and LTE-advanced (LTE-a) are new releases of Universal Mobile
Telecommunications System (UMTS) that use E-UTRA. UTRA, E-UTRA, Universal Mobile Telecommunications
System (UMTS), LTE, LTE-a, and Global System for Mobile communications (GSM) are described
in documents from an organization named "3rd Generation Partnership Project" (3GPP).
CDMA2000 and UMB are described in documents from an organization named "3rd Generation
Partnership Project 2" (3GPP2). The techniques described herein may be used for the
systems and radio technologies mentioned above as well as other systems and radio
technologies. The description herein, however, describes an LTE system for purposes
of example, and LTE terminology is used in much of the description above, although
the techniques are applicable beyond LTE applications.
[0097] In LTE/LTE-a networks, including such networks described herein, the term evolved
node B (eNB) may be generally used to describe the base stations. The wireless communications
system or systems described herein may include a heterogeneous LTE/LTE-a network in
which different types of evolved node B (eNBs) provide coverage for various geographical
regions. For example, each eNB or base station may provide communication coverage
for a macro cell, a small cell, or other types of cell. The term "cell" is a 3GPP
term that can be used to describe a base station, a carrier or component carrier associated
with a base station, or a coverage area (
e.g., sector,
etc.) of a carrier or base station, depending on context.
[0098] Base stations may include or may be referred to by those skilled in the art as a
base transceiver station, a radio base station, an access point, a radio transceiver,
a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitable terminology.
The geographic coverage area for a base station may be divided into sectors making
up only a portion of the coverage area. The wireless communications system or systems
described herein may include base stations of different types (
e.g., macro or small cell base stations). The UEs described herein may be able to communicate
with various types of base stations and network equipment including macro eNBs, small
cell eNBs, relay base stations, and the like. There may be overlapping geographic
coverage areas for different technologies.
[0099] A macro cell generally covers a relatively large geographic area (
e.g., several kilometers in radius) and may allow unrestricted access by UEs with service
subscriptions with the network provider. A small cell is a lower-powered base station,
as compared with a macro cell, that may operate in the same or different (
e.g., licensed, unlicensed,
etc.) frequency bands as macro cells. Small cells may include pico cells, femto cells,
and micro cells according to various examples. A pico cell, for example, may cover
a small geographic area and may allow unrestricted access by UEs with service subscriptions
with the network provider. A femto cell may also cover a small geographic area (
e.g., a home) and may provide restricted access by UEs having an association with the femto
cell (
e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like).
An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell
may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An
eNB may support one or multiple (
e.g., two, three, four, and the like) cells (
e.g., component carriers). A UE may be able to communicate with various types of base stations
and network equipment including macro eNBs, small cell eNBs, relay base stations,
and the like.
[0100] The wireless communications system or systems described herein may support synchronous
or asynchronous operation. For synchronous operation, the base stations may have similar
frame timing, and transmissions from different base stations may be approximately
aligned in time. For asynchronous operation, the base stations may have different
frame timing, and transmissions from different base stations may not be aligned in
time. The techniques described herein may be used for either synchronous or asynchronous
operations.
[0101] The downlink transmissions described herein may also be called forward link transmissions
while the uplink transmissions may also be called reverse link transmissions. Each
communication link described herein-including, for example, wireless communication
system 100 and 200 of FIGs. 1 and 2-may include one or more carriers, where each carrier
may be a signal made up of multiple sub-carriers (
e.g., waveform signals of different frequencies). Each modulated signal may be sent on
a different sub-carrier and may carry control information (
e.g., reference signals, control channels,
etc.)
, overhead information, user data,
etc. The communication links described herein (
e.g., communication links 125 of FIG. 1) may transmit bidirectional communications using
frequency division duplex (FDD) (
e.g., using paired spectrum resources) or time division duplex (TDD) operation (
e.g., using unpaired spectrum resources). Frame structures may be defined for frequency
division duplex (FDD) (
e.g., frame structure type 1) and TDD (
e.g., frame structure type 2).
[0102] The description set forth herein, in connection with the appended drawings, describes
example configurations and does not represent all the examples that may be implemented
or that are within the scope of the claims. The term "exemplary" used herein means
"serving as an example, instance, or illustration," and not "preferred" or "advantageous
over other examples." The detailed description includes specific details for the purpose
of providing an understanding of the described techniques. These techniques, however,
may be practiced without these specific details. In some instances, well-known structures
and devices are shown in block diagram form in order to avoid obscuring the concepts
of the described examples.
[0103] In the appended figures, similar components or features may have the same reference
label. Further, various components of the same type may be distinguished by following
the reference label by a dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the specification, the description
is applicable to any one of the similar components having the same first reference
label irrespective of the second reference label.
[0104] Information and signals described herein may be represented using any of a variety
of different technologies and techniques. For example, data, instructions, commands,
information, signals, bits, symbols, and chips that may be referenced throughout the
above description may be represented by voltages, currents, electromagnetic waves,
magnetic fields or particles, optical fields or particles, or any combination thereof.
[0105] The various illustrative blocks and modules described in connection with the disclosure
herein may be implemented or performed with a general-purpose processor, a digital
signal processor (DSP), an ASIC, an FPGA or other programmable logic device, discrete
gate or transistor logic, discrete hardware components, or any combination thereof
designed to perform the functions described herein. A general-purpose processor may
be a microprocessor, but in the alternative, the processor may be any conventional
processor, controller, microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices (
e.g., a combination of a digital signal processor (DSP) and a microprocessor, multiple
microprocessors, one or more microprocessors in conjunction with a DSP core, or any
other such configuration).
[0106] The functions described herein may be implemented in hardware, software executed
by a processor, firmware, or any combination thereof. If implemented in software executed
by a processor, the functions may be stored on or transmitted over as one or more
instructions or code on a computer-readable medium.
[0107] For example, due to the nature of software, functions described above can be implemented
using software executed by a processor, hardware, firmware, hardwiring, or combinations
of any of these. Features implementing functions may also be physically located at
various positions, including being distributed such that portions of functions are
implemented at different physical locations. Also, as used herein, including in the
claims, "or" as used in a list of items (for example, a list of items prefaced by
a phrase such as "at least one of" or "one or more of') indicates an inclusive list
such that, for example, a list of at least one of A, B, or C means A or B or C or
AB or AC or BC or ABC (
i.e., A and B and C).
[0108] Computer-readable media includes both non-transitory computer storage media and communication
media including any medium that facilitates transfer of a computer program from one
place to another. A non-transitory storage medium may be any available medium that
can be accessed by a general purpose or special purpose computer. By way of example,
and not limitation, non-transitory computer-readable media can comprise RAM, ROM,
electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM
or other optical disk storage, magnetic disk storage or other magnetic storage devices,
or any other non-transitory medium that can be used to carry or store desired program
code means in the form of instructions or data structures and that can be accessed
by a general-purpose or special-purpose computer, or a general-purpose or special-purpose
processor. Also, any connection is properly termed a computer-readable medium. For
example, if the software is transmitted from a website, server, or other remote source
using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL),
or wireless technologies such as infrared, radio, and microwave, then the coaxial
cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared, radio, and microwave are included in the definition
of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital
versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data
magnetically, while discs reproduce data optically with lasers. Combinations of the
above are also included within the scope of computer-readable media.
[0109] The description herein is provided to enable a person skilled in the art to make
or use the disclosure. Various modifications to the disclosure will be readily apparent
to those skilled in the art, and the generic principles defined herein may be applied
to other variations without departing from the scope of the disclosure. The invention
is defined by the appended claims.